Space camera long-focus plane assembly thermal structural stability test platform and test method

Abstract

The application discloses a long-focus plane assembly thermal structure stability test platform and a test method for a space camera, positions a long-focus plane assembly on an optical splicing platform, measures initial splicing precision of the long-focus plane assembly, and connects a thermal test platform; by starting a heating loop, a thermal environment in an imaging process of the long-focus plane assembly is simulated, temperatures of temperature measuring points at different imaging times are monitored, and a temperature rise curve in the imaging process of the long-focus plane assembly, point temperature peaks and a temperature gradient are obtained; splicing precision of a detector after imaging is measured through the optical splicing platform, that is, splicing precision of the long-focus plane assembly under actual working conditions; finally, by comparing variation amounts of the detector position precision of the long-focus plane assembly after optical splicing and imaging heating tests, influence of heating in an on-orbit imaging process of the long-focus plane assembly on the position precision can be obtained.

Description

Technical Field

[0001] This invention relates to the field of space optical remote sensing technology, and in particular to a test platform and test method for the thermal structural stability of long focal plane components of space cameras. Background Technology

[0002] In the field of space optical remote sensing technology, the dimensional stability of long focal plane components is one of the core indicators affecting image quality. Especially in applications such as high-precision remote sensing and space observation, the thermal stability of collinearity and coplanarity between detectors directly determines the accuracy of image synthesis and system reliability.

[0003] Currently, the positional accuracy of detectors in long focal plane arrays is measured using an optical splicing platform. Stability is assessed by testing the detector splicing accuracy before and after vibration and thermal cycling tests, comparing the impact of stress release caused by force and thermal disturbances on detector collinearity and coplanarity. While this method reflects the array's environmental adaptability, it only collects data on the stable state before and after testing, failing to monitor the dynamic thermal deformation process of the long focal plane array under actual operating conditions in real time. Furthermore, existing methods rely on external thermal cycling excitation, making it difficult to simulate temperature changes and transient thermal disturbances caused by the detector's own heating, leading to certain deviations in predicting structural deformation under actual operating conditions.

[0004] Based on the above-mentioned technical problems, those skilled in the art urgently need to develop a new testing platform and method that can track the thermal deformation of the long focal plane assembly structure in real time under working conditions and obtain its impact on the collinearity and coplanarity accuracy of the detector, so as to improve the evaluation accuracy and reliability of the thermal stability of the long focal plane assembly. Summary of the Invention

[0005] The purpose of this invention is to provide a test platform and method for the thermal structural stability of a space camera's long focal plane assembly, which can track the thermal deformation of the long focal plane assembly structure in real time under working conditions and obtain its impact on the collinearity and coplanarity accuracy of the detector, thereby improving the evaluation accuracy and reliability of the thermal stability of the long focal plane assembly.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The present invention provides a thermal structural stability testing platform for a space camera focal plane assembly, the testing platform comprising:

[0008] Optical splicing platform and thermal testing platform; among them,

[0009] The optical splicing platform includes a mechanical reference frame to provide rigid support for the long focal plane assembly; and

[0010] The detection computer can acquire images of the detector's marked points, obtain their coordinates, and calculate flatness and collinearity accuracy.

[0011] A video detection system that outputs the image from the detector to the detection computer;

[0012] Air-floating vibration isolation platforms are used to isolate or reduce the effects of external vibrations.

[0013] Precision air-bearing guide rails are used to realize the movement and positioning of the video detection system;

[0014] The thermal testing platform includes a temperature measurement and control system capable of controlling the heating power consumption of the heater. It has a temperature acquisition instrument with several acquisition cards, each of which has multiple measurement channels; and

[0015] A power supply with a fixed output frequency;

[0016] Temperature control equipment, capable of controlling the heating power of the heating circuit;

[0017] The main control box and integrated simulation equipment are used. The main control box is the central control hub of the thermal test system, and the integrated simulation equipment can simulate the thermal environment of the long focal plane component under actual working conditions.

[0018] Furthermore, a polyimide film heating element is attached to the long focal plane assembly. The polyimide film heating element and the detector together form a heating circuit, and the heating power consumption of the heating circuit is 3W and 9W respectively, which is used to simulate the thermal environment of the focal plane substrate under actual working conditions.

[0019] A beam splitter is installed in the long focal plane assembly.

[0020] Preferably, the video detection system consists of a high-powered microscope and an imaging system.

[0021] Preferably, the power supply output frequency is fixed at 1Hz, the duty cycle is adjustable between 0% and 100%, and the output voltage value can be from 0V to the bus voltage.

[0022] Preferably, the temperature acquisition instrument is model Keysight34972, which contains 3 acquisition cards, each with 20 measurement channels, and provides a local area network (LAN) interface and a universal serial bus (USB) interface.

[0023] Based on the above, the method for testing the focal plane stability of a space camera is summarized as follows: The long focal plane assembly is positioned on an optical stitching platform, its initial stitching accuracy is measured, and a thermal test platform is connected. By activating the heating circuit, the thermal environment during the imaging process of the long focal plane assembly is simulated, and the temperature at each measurement point is monitored at different imaging times to obtain the temperature rise curve, peak temperature at each point, and temperature gradient during the imaging process of the long focal plane assembly. The stitching accuracy of the detector after imaging is measured using the optical stitching platform, which is the stitching accuracy of the long focal plane assembly under actual working conditions. Finally, by comparing the changes in the detector position accuracy of the long focal plane assembly after optical stitching and imaging heating tests, the influence of heating on position accuracy during on-orbit imaging of the long focal plane can be determined.

[0024] The thermal structural stability test platform and testing method for the long focal plane assembly of a space camera provided by the present invention have the following beneficial effects:

[0025] The fundamental purpose of the thermal structural stability test platform and testing method for the long focal plane assembly of a space camera in this invention is to evaluate the collinearity and coplanarity accuracy stability between detectors under thermal conditions. By integrating an optical stitching platform and a thermal test platform, the actual working heating state of the focal plane assembly is simulated to obtain the influence of thermoelastic deformation on stitching accuracy. Through temperature field simulation and multi-parameter adjustable thermal load excitation, the temperature distribution of the focal plane in orbit is simulated to solve the problem of deviation between static detection and actual working conditions, thereby enhancing the reliability of the long focal plane assembly in complex thermal environments. At the same time, by quantifying the relationship between heat source and thermoelastic deformation, changes in stitching accuracy can be predicted in advance, reducing the risk of on-orbit failure and lowering maintenance costs.

[0026] This invention can optimize structural design. The above-mentioned testing method can help engineers better understand the relationship between focal plane heat source and thermoelastic deformation, providing data support for the optimization of structural design and heat source layout, thereby improving the thermal stability design level of long focal plane components. At the same time, it expands application scenarios, enabling long focal plane components to adapt to more stringent on-orbit environments, and promoting performance breakthroughs and application scope expansion in the field of aerospace cameras. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0028] Figure 1 This is a schematic diagram of the optical splicing platform in the thermal structural stability test platform for the long focal plane component of a space camera provided in an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the thermal testing platform in the thermal structural stability testing platform for the long focal plane component of a space camera provided in an embodiment of the present invention;

[0030] Figure 3 The splicing test results of the long focal plane component detector in the XY direction in the thermal structure stability test method of the long focal plane component of the space camera provided in the embodiment of the present invention;

[0031] Figure 4 The splicing test results of the long focal plane component detector in the Z direction in the thermal structure stability test method of the long focal plane component of the space camera provided in the embodiment of the present invention;

[0032] Figure 5 The stitching test results of the long focal plane component detector in the XY direction after 300s imaging in the thermal structure stability test method of the space camera long focal plane component provided in the embodiment of the present invention;

[0033] Figure 6 The image shows the stitching test results of the long focal plane component detector in the Z direction after 300s imaging in the thermal structure stability test method of the space camera long focal plane component provided in the embodiment of the present invention.

[0034] Explanation of reference numerals in the attached figures:

[0035] 1. Mechanical reference frame; 2. Long focal length plane assembly; 3. Video inspection system; 4. Detector; 5. Inspection computer; 6. Air-bearing vibration isolation platform; 7. Precision air-bearing guide rail; 8. Temperature measurement and control system; 9. Temperature control equipment; 10. Main control box and integrated simulation equipment; 11. Power supply;

[0036] 201. Polyimide film heating element; 202. Beam splitter. Detailed Implementation

[0037] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0038] See Figures 1-6 As shown;

[0039] The present invention provides a thermal structural stability testing platform for a space camera focal plane assembly, the testing platform comprising:

[0040] An optical stitching platform and a thermal testing platform are integrated to simulate and verify the stability of the relative positional accuracy between detectors during on-orbit imaging; among them,

[0041] The optical splicing platform includes a mechanical reference frame 1, which provides rigid support for the long focal plane assembly 2, avoiding errors introduced by structural deformation during testing; and

[0042] The detection computer 5 can acquire images of the marked points of the detector 4, obtain their coordinates, and calculate the flatness and collinearity accuracy. The collinearity and coplanarity accuracy of the detector 4 directly affects the imaging performance of the system.

[0043] The video detection system 3 is capable of outputting the image of the detector 4 to the detection computer 5;

[0044] The air-floating vibration isolation platform 6 can isolate or reduce the influence of external vibrations, providing a highly stable platform for the optical splicing platform;

[0045] The precision air-bearing guide rail 7 is used to realize the movement and positioning of the video detection system 3;

[0046] The optical splicing platform measurement process involves displaying the image of the detector 4 pixels on the detection computer 5 using a high-magnification microscope and imaging system, and using a precision air-bearing guide rail 7 to carry the microscope head and video imaging system for three-dimensional movement to measure the spatial position of each marker point of the detector pixel, calculate the flatness and collinearity accuracy, and realize the optical splicing accuracy evaluation of the long focal plane component 2.

[0047] The thermal testing platform includes a temperature measurement and control system 8, which can control the heating power consumption of the heater and configure temperature measurement points on the coke surface substrate. The temperature at each point is measured by thermocouple temperature sensors. The system also includes a temperature acquisition instrument with several acquisition cards, each of which has multiple measurement channels.

[0048] Power supply 11 has a fixed output frequency;

[0049] Temperature control device 9 can accurately control the heating power of the heating circuit to ensure the consistency of heat load with actual working conditions;

[0050] The main control box and integrated simulation equipment 10 are as follows: the main control box is the central control hub of the thermal test system, ensuring the coordinated operation of the thermal test platform and the optical splicing platform; the integrated simulation equipment can simulate the thermal environment of the long focal plane component 2 under actual working conditions.

[0051] As a further introduction to this embodiment, a polyimide film heating element 201 is attached to the long focal plane assembly 2. The polyimide film heating element 201 and the detector 4 are jointly formed, and the heating power consumption of the heating circuit is 3W and 9W respectively, which are used to simulate the thermal environment of the focal plane substrate under actual working conditions.

[0052] A beam splitter 202 is installed in the long focal plane assembly 2.

[0053] As a preferred technical solution in this embodiment, the video detection system 3 consists of a high-magnification microscope and an imaging system.

[0054] As a preferred technical solution in this embodiment, the power supply 11 has a fixed output frequency of 1Hz, an adjustable duty cycle between 0% and 100%, and can achieve an effective output voltage value of 0V to bus voltage.

[0055] As a preferred technical solution in this embodiment, the temperature acquisition instrument is model Keysight34972, which contains 3 acquisition cards, each with 20 measurement channels, and provides a local area network (LAN) interface and a universal serial bus (USB) interface.

[0056] The present invention provides a method for testing the thermal structural stability of a long focal plane component of a space camera, the method comprising the following steps:

[0057] Step 1: Install the high-stability mechanical reference frame 1 and video detection system 3 on the air-bearing vibration isolation platform 6, and fix the precision air-bearing guide rail 7 to ensure that the X, Y, and Z axis motion range of the precision air-bearing guide rail 7 covers the measurement area of ​​the long focal plane assembly 2;

[0058] Step 2: Adjust the position of the telephoto plane component 2 so that the coordinate system of the telephoto plane component 2 is consistent with the motion coordinate system of the precision air bearing guide rail 7, and complete the positioning of the telephoto plane component 2 on the splicing platform.

[0059] Step 3: Measure the angle between the mirror surface of beam splitter 202 and the mounting surface, and control the angle by refining.

[0060] Step 4: Attach the polyimide film heating element 201 and the detector 4 to the long focal plane assembly 2 to form a heating circuit, code H, and configure the corresponding temperature measuring points, code T for the temperature measuring circuit;

[0061] Step 5: Connect the heating circuit to the power distribution box 11, and connect the temperature measurement circuit to the temperature measurement and control system 8;

[0062] Step 6: Move the XY axis of the precision air-bearing guide rail 7 so that the crosshairs of the detection computer 5 overlap with the center of the first mark point of the first detector 4, and adjust the Z axis of the precision air-bearing guide rail 7 so that the detection computer 5 focuses on the mark point of the detector 4. Set the spatial position of this point in the detection computer 5 as (0, 0, 0).

[0063] The remaining marker points are detected and their corresponding three-dimensional spatial coordinates are recorded. The spatial positions of the four marker points of each detector are obtained through detection, such as... Figure 3 and Figure 4 As shown, the initial collinearity of detector 4 in the long focal plane assembly 2 is calculated to be 1.8 μm and the coplanarity is 3.8 μm.

[0064] Step 7: Start the power supply 11 distribution box, turn on the heating circuit for 300s, simulate the imaging work of the long focal plane component 2, monitor the temperature of each temperature measuring point, and obtain the effect of imaging time on the long focal plane component 2.

[0065] Step 8: The image of the detector pixel is displayed on the detection computer 5 by the video detection system 3. The video detection system 3 is then moved in three dimensions using a precision air-bearing guide rail 7 to measure the spatial position of each marker point of the detector 4 pixel. Figure 5 and Figure 6 As shown, by repeating step six, the collinearity of detector 4 after imaging of the long focal plane component 2 is obtained as 2.8 μm and the coplanarity as 3.5 μm.

[0066] Step 9: Compare the changes in the position accuracy of detector 4 of the long focal plane assembly 2 after optical stitching and imaging heating tests. The collinearity and coplanarity of detector 4 decreased by 1.0 μm and 0.3 μm, respectively. This shows the influence of heating of the long focal plane assembly 2 on the position accuracy during on-orbit imaging, thus verifying that the long focal plane assembly 2 has sufficient dimensional stability to ensure the relative position accuracy between detectors during on-orbit imaging.

[0067] As a preferred technical solution in this embodiment, in step three, the angle between the beam splitter 202 and the mounting surface is controlled to be 45° by refining.

[0068] As a preferred technical solution in this embodiment, in step five, the power supply 11 distribution box outputs a frequency of 1Hz, with a duty cycle adjustable from 0% to 100%, and an output voltage of 0V to bus voltage.

[0069] The temperature measurement circuit is connected to three acquisition cards of the temperature acquisition instrument, with a total of 60 measurement channels, and is connected to the detection computer 5 via a LAN / USB interface.

[0070] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for testing the thermal structural stability of a long focal plane component in a space camera, characterized in that, This testing method was performed using an experimental platform, which included: Optical splicing platform and thermal testing platform; among them, The optical splicing platform includes a mechanical reference frame (1) that provides rigid support for the long focal plane assembly (2); and The detection computer (5) can acquire images of the marker points of the detector (4), obtain their coordinates, and calculate the flatness and collinearity accuracy. The video detection system (3) is capable of outputting the image of the detector (4) to the detection computer (5); Air-floating vibration isolation platform (6) is used to isolate or reduce the effects of external vibrations; A precision air-bearing guide rail (7) is used to realize the movement and positioning of the video detection system (3); The thermal testing platform includes a temperature measurement and control system (8), which can control the heating power consumption of the heater. It has a temperature acquisition instrument with several acquisition cards, each with multiple measurement channels; and Power supply (11), which has a fixed output frequency; Temperature control device (9) can control the heating power of the heating circuit; The main control box and integrated simulation equipment (10) are the central control hub of the thermal test system, and the integrated simulation equipment can simulate the thermal environment of the long focal plane component (2) under actual working conditions. The testing method includes the following steps: Step 1: Install a high-stability mechanical reference frame (1) and a video detection system (3) on the air-bearing vibration isolation platform (6), and fix the precision air-bearing guide rail (7) to ensure that the X, Y, and Z three-axis motion range of the precision air-bearing guide rail (7) covers the measurement area of ​​the long focal plane assembly (2); Step 2: Adjust the position of the long focal plane assembly (2) so that the coordinate system of the long focal plane assembly (2) is consistent with the motion coordinate system of the precision air bearing guide rail (7) to complete the positioning of the long focal plane assembly (2) on the splicing platform; Step 3: Measure the angle between the mirror surface of the beam splitter (202) and the mounting surface, and control the angle by refining; Step 4: Attach the polyimide film heating element (201) and the detector (4) to the long focal plane assembly (2) to form a heating circuit, code H, and configure the corresponding temperature measuring points, code T; Step 5: Connect the heating circuit to the power supply (11) distribution box and connect the temperature measurement circuit to the temperature measurement and control system (8). Step 6: Move the XY axis of the precision air-bearing guide rail (7) so that the crosshairs of the detection computer (5) overlap with the center of the first mark point of the first detector (4), and adjust the Z axis of the precision air-bearing guide rail (7) so that the detection computer (5) focuses on the mark point of the detector (4). Set the spatial position of the point in the detection computer (5) as (0, 0, 0). The three-dimensional spatial coordinates of the remaining marker points are detected and recorded. The spatial position of each detector (4) marker point is obtained by detection, and the initial collinearity and coplanarity of the detector (4) in the long focal plane assembly (2) are calculated. Step 7: Start the power supply (11) distribution box, turn on the heating circuit for 300s, simulate the imaging work of the long focal plane component (2), monitor the temperature of each temperature measuring point, and obtain the effect of imaging time on the long focal plane component (2); Step 8: Display the image of the detector pixel on the detection computer (5) through the video detection system (3), and use the precision air-bearing guide rail (7) to carry the video detection system (3) to move in three dimensions to measure the spatial position of each marker point of the detector (4) pixel. Repeat step 6 to obtain the collinearity and coplanarity of the detector (4) after the long focal plane component (2) is imaged. Step 9: Compare the changes in the position accuracy of the detector (4) of the long focal plane assembly (2) after optical splicing and imaging heating tests. The collinear and coplanar accuracy of the detector (4) decreased by 1.0 μm and 0.3 μm, respectively. This shows the effect of the heating of the long focal plane assembly (2) on the position accuracy during on-orbit imaging, thus verifying that the long focal plane assembly (2) has sufficient dimensional stability to ensure the relative position accuracy between the detectors (4) during on-orbit imaging.

2. The method for testing the thermal structural stability of a space camera's long focal plane assembly according to claim 1, characterized in that, The heating circuits consume 3W and 9W of power respectively to simulate the thermal environment of the focal surface substrate under actual working conditions.

3. The method for testing the thermal structural stability of a space camera's long focal plane assembly according to claim 1, characterized in that, The video detection system (3) consists of a high-power microscope and an imaging system.

4. The method for testing the thermal structural stability of a space camera's long focal plane assembly according to claim 1, characterized in that, The power supply (11) has a fixed output frequency of 1Hz and an adjustable duty cycle between 0% and 100%, and can achieve an output voltage value of 0V to bus voltage.

5. The method for testing the thermal structural stability of a space camera's long focal plane assembly according to claim 1, characterized in that, The temperature acquisition instrument, model Keysight34972, contains three acquisition cards, each with 20 measurement channels, and provides a LAN interface and a USB interface.

6. The method for testing the thermal structural stability of a space camera's long focal plane assembly according to claim 1, characterized in that, In step three, the angle between the beam splitter (202) and the mounting surface is adjusted to 45°.

7. The method for testing the thermal structural stability of a space camera's long focal plane assembly according to claim 1, characterized in that, In step five, the power supply (11) distribution box outputs a frequency of 1Hz, with a duty cycle adjustable from 0% to 100%, and an output voltage of 0V to the bus voltage. The temperature measurement circuit is connected to three acquisition cards of the temperature acquisition instrument, with a total of 60 measurement channels, and is connected to the detection computer (5) via LAN / USB interface.

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